Example-Based CADx Feature Selection for Radiologist Workflows

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Solution Overview

Problem

Radiologists face 'information overload' when interpreting medical scans, leading to potential missed cancers and false positives, necessitating improved decision support systems for accurate diagnosis.

Innovation Solution

An example-based computer-aided diagnosis (CADx) system that uses a genetic algorithm to select an optimal set of volume-of-interest (VOI) features and distance metrics, incorporating subjective radiologist assessments to objectively cluster and retrieve similar tumor examples from a database, ensuring accurate visual comparison and diagnosis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If radiologists manually interpret medical scan images, then diagnostic experience and visual assessment are utilized, but information overload occurs and diagnostic accuracy decreases due to missed cancers and false positives

Engineering Contradiction:
Improvediagnostic accuracyVSAvoidinformation processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a computer-based intermediary system that automatically extracts features from medical images, computes similarity metrics, and retrieves relevant examples from a database. This intermediary handles the complex information processing task, freeing radiologists from direct manual analysis of all images while providing targeted assistance through retrieved examples that improve diagnostic accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical process of manual visual inspection by radiologists with an automated computational system that uses feature extraction, mathematical similarity metrics (such as Euclidean distance in feature space), and database querying algorithms. This substitution eliminates human fatigue and inconsistency while maintaining diagnostic quality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If example-based CADx retrieves tumors based on visual similarity, then relevant cases are provided for comparison, but subjective variability among radiologists leads to inconsistent similarity assessments

Engineering Contradiction:
Improvesimilarity assessment flexibilityVSAvoidsimilarity measurement consistency
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent transforms the subjective visual assessment of tumor similarity into objective parameter-based measurements. Multiple features (size, shape, texture, density) are extracted and represented as numerical parameters in a feature space. Similarity is then measured using consistent mathematical metrics such as Euclidean distance, ensuring that the same two tumors will always yield the same similarity score regardless of which radiologist evaluates them.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent moves the similarity assessment from a single-dimensional visual comparison to a multi-dimensional feature space where tumors are represented by multiple parameters simultaneously. This dimensional expansion allows for more nuanced and accurate similarity measurement by considering multiple characteristics of tumors rather than relying solely on overall visual appearance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If all tumor features are used for database retrieval, then comprehensive comparison is achieved, but retrieval efficiency decreases and false positives increase

Engineering Contradiction:
Improvediagnosis accuracyVSAvoidretrieval efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent extracts and selects only the most discriminative and relevant features from the complete set of available tumor characteristics. Through feature selection methods, the system identifies and retrieves a subset of key features that provide the best balance between diagnostic accuracy and retrieval efficiency, excluding redundant or less informative features that would slow down the process or introduce noise.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements a balanced approach where not all possible features are used, but rather a carefully selected partial set that provides sufficient diagnostic information. This partial action approach avoids the excessive processing of all available features while maintaining adequate retrieval accuracy through the use of the most informative subset.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS8185511B2Clinician-driven example-based computer-aided diagnosis
Publication Date: 2012.05.22 KONINKLIJKE PHILIPS NV
  • US8185511B2 patent drawing
  • US8185511B2 patent drawing
  • US8185511B2 patent drawing

AI summary

Optimizing example-based computer-aided diagnosis (CADx) is accomplished by clustering volumes-of-interest (VOIs) (116) in a database (120) into respective clusters according to subjective assessment of similarity (S220). An optimal set of volume-of-interest (VOI) features is then selected for fetching examples such that objective assessment of similarity, based on the selected features, clusters, in a feature space, the database VOIs so as to conform to the subjectively-based clustering (S230). The fetched examples are displayed alongside the VOI to be diagnosed for comparison by the clinician. Preferably, the displayed example is user-selectable for further display of prognosis, therapy information, follow up information, current status, and/or clinical information retrieved from an electronic medical record (S260).